/* $Id$ */

/** @file tunnelbridge_map.h Functions that have tunnels and bridges in common */

#ifndef TUNNELBRIDGE_MAP_H

#define TUNNELBRIDGE_MAP_H

#include "direction.h"            /* DiagDirection */

#include "core/bitmath_func.hpp"  /* GB, HasBit, SB */

#include "map.h"                  /* Tile, TileIndex */

#include "tile.h"                 /* TileType, IsTileType */

#include "openttd.h"              /* TransportType */

/**

 * Tunnel: Get the direction facing out of the tunnel

 * Bridge: Get the direction pointing onto the bridge

 * @param t The tile to analyze

 * @pre IsTileType(t, MP_TUNNELBRIDGE)

 * @return the above mentionned direction

 */

static inline DiagDirection GetTunnelBridgeDirection(TileIndex t)

{

	assert(IsTileType(t, MP_TUNNELBRIDGE));

	return (DiagDirection)GB(_m[t].m5, 0, 2);

}

/**

 * Tunnel: Get the transport type of the tunnel (road or rail)

 * Bridge: Get the transport type of the bridge's ramp

 * @param t The tile to analyze

 * @pre IsTileType(t, MP_TUNNELBRIDGE)

 * @return the transport type in the tunnel/bridge

 */

static inline TransportType GetTunnelBridgeTransportType(TileIndex t)

{

	assert(IsTileType(t, MP_TUNNELBRIDGE));

	return (TransportType)GB(_m[t].m5, 2, 2);

}

/**

 * Tunnel: Is this tunnel entrance in a snowy or desert area?

 * Bridge: Does the bridge ramp lie in a snow or desert area?

 * @param t The tile to analyze

 * @pre IsTileType(t, MP_TUNNELBRIDGE)

 * @return true if and only if the tile is in a snowy/desert area

 */

static inline bool HasTunnelBridgeSnowOrDesert(TileIndex t)

{

	assert(IsTileType(t, MP_TUNNELBRIDGE));

	return HasBit(_m[t].m4, 7);

}

/**

 * Tunnel: Places this tunnel entrance in a snowy or desert area, or takes it out of there.

 * Bridge: Sets whether the bridge ramp lies in a snow or desert area.

 * @param t the tunnel entrance / bridge ramp tile

 * @param snow_or_desert is the entrance/ramp in snow or desert (true), when

 *                       not in snow and not in desert false

 * @pre IsTileType(t, MP_TUNNELBRIDGE)

 */

static inline void SetTunnelBridgeSnowOrDesert(TileIndex t, bool snow_or_desert)

{

	assert(IsTileType(t, MP_TUNNELBRIDGE));

	SB(_m[t].m4, 7, 1, snow_or_desert);

}

#endif /* TUNNELBRIDGE_MAP_H */